let wangtian:any;
function test(){
    document.write("任意类型初始值："+wangtian);
    wangtian="望天";
    document.write("<p>任意类型："+wangtian);
    wangtian = 7;
    let name = `望狗！${wangtian}号`;
    document.write("<p>任意类型："+name);
}
test();